Figure 2. Self-monitoring device used in the randomized trial. Portable handy-sized urinary Na/K ratio monitor (HEU-001F, OMRON Healthcare Co., Ltd., Kyoto, Japan) used for self-monitoring of the dietary lifestyle of the participants during the randomized trial. This device measures urinary Na and K concentrations, and calculates urinary Na/K ratio via ion selective electrodes. Only participants in the “device + usual care” intervention group were given the monitoring device. These participants were then asked to measure at least one spot urine Na/K ratio daily.